A disc brake has a disc and brake pads, and generally each brake pad includes a lining (friction material) for braking the disc and a back plate for supporting the lining. Since this back plate supports the lining, it is required to have heat resistance, brake resistance, and high mechanical strength in a high temperature atmosphere. For this reason, conventionally, plates made of ceramic or plates made of metal have been used for the back plate. However, when the plates made of ceramic and the plates made of metal are used for the back plate, there are problems such as a heavy weight, a long time required for machining, high costs, and the like.
Therefore, recently, it is attempted to use a plate made of a synthetic resin mixed with fibers for the back plate instead of the plates made of metal for the purpose of reducing both weight and cost.
As technology relating to this type of back plate, Patent Document 1 discloses a back plate that uses a carbon fiber reinforced plastic plate.
However, since such a back plate is formed of a molding material composed of one type of fibers mixed with the synthetic resin, it is necessary to contain the fibers in the molding material in a large amount in order to improve the mechanical strength. In this case, however, there is a problem in that viscosity of the molding material increases, and moldability thereof decreases.